It has previously been proposed to determine the speed of rotation of a shaft by placing a magnetic transducer element in magnetically coupled relation with a star wheel, or toothed disk. A typical application is the determination of the speed of rotation of an internal combustion engine, and especially of an automotive type internal combustion engine. The transducer can be located in magnetically coupled relationship to the main starter gear, connected to the flywheel of the internal combustion (IC) engine. The magnetic pickup, typically, is a coil, or a core on which a coil is wound which is so placed that as the teeth of the gear, or of the star wheel pass the core of the pickup, the magnetic reluctance of the magnetic circuit of which the pickup is a part changes, thus providing changing output signals. The speed of rotation of this shaft is then determined by relating the output signals to a time reference. If it is additionally desired to obtain a reference signal representative of a particular angular position of the shaft which, in an IC engine would correspond to a specific angular position of a piston in the engine, then it has been customary to provide a second disk, or ring cooperating with a second pickup coil. It is frequently difficult to locate a second rotating element on the shaft and to place a second pickup unit. Additionally, the star wheel, typically the starter gear, and the second or reference element rotating therewith must be accurately angularly positioned so that the signals derived from the respective pickups will be coordinate. The provision of a second rotating disk and pickup is expensive and requires additional installation cost, if space considerations permit its use.